I  4- 


- 


I  January  »,  r.>12 


U.S.  DEPARTMENT   OF  AGRICULTURE, 

BUREAU   OF   ENTOMOLOGY     CIRCULAR   No.   111. 

L.  O.  HOWARD.  Enlomologul  and  Chwf  o(  Bui«u 


THE   DYING   IIK'KOKV  TREES 

CAl  SE  AMI  REMEDY. 


BY 


A.   D.    HOPKINS, 
Fn  Charge  of  For  I  In  instigations. 


■  i     iu 


•A»HIIMJTO»<  :  OOVCRXHEXT   PRINTISQ  o«lCE  :  1t12 


BUREAU  OF  ENTOMOLOGY. 

L.  O.  Howabd,  Entomologist  and  Chief  of  Bureau. 

C.  L.  Marlatt,  Entomologist  and  Acting  Chief  in  Absence  of  Chief. 

It.  S.  Clifton,  Executive  Assistant. 

W.  F.  Tastit,  Chief  fieri:. 

F.  H.  Chittenden,  fa  charge  of  truck  crop  and  stored  product  insect  investiga- 
tions. 
A.  D.  Hopkins,  in  charge  of  forest  insect  investigations. 

W.  I>.  Hunter,  in  charge  of  southern  field  crop  insect  investigations. 

V.  M.  Webster,  in  charge  of  cereal  and  forage  insect  investigations. 

A.  L.  Quaintanc'e,  in  charge  of  deciduous  fruit  insect  investigations. 

E.  F.  Phillips,  in  charge  of  bee  culture. 

I).  M.  Rogers,  in  charge  of  preventing  spread  of  moths,  field  work. 

Rolla  P.  Currie.  fa  charge  of  editorial  work. 

Mabel  Colcobd,  fa  charge  of  library. 

Forest  Insect  Investigations. 

A.  D.  Hopkins,  in  charge. 

H.  E.  Bcrke,  entomological  assistant,  in  chargi   of  Forest  insect  Field  Station'}, 

Yreka,  Cal. 
W.  D.  Edmonston.  agent  and  expert,  in  charge  of  Forest  insect  Field  Station  (I. 

Klamath   Falls.   Oreg. 
Josef  Bbtjnnes,  agent  and  expert,  in  charge  of  Forest  Insect   Field  station  J. 

Columbia  Falls,  Mont. 
E.  B.  Mason,  entomological  assistant,  in  charge  of  Forest  Insect  Field  Station  7, 

Spartanburg,  8.  C. 
T.  E.  Snydeb,  agent  and  expert,  engaged  in  investigations  of  insect  damage  to 

telegraph   and   telephone  poles. 
J.  L.  Webb,  entomological  assistant,  specialist  on  cerambycid  beetles  and  larva'. 
S.  A.  Rohweb,  agent  and  expert,  specialist  on  saw  flies  iTcnlhrcdinoidea  >. 
Mary  E.  Fatjnce,  Mary  C.  Johnson.  Maude  Taylor.  Elizabeth  Ritchie,  pre- 

parators. 
ii 


Circular  No.   144. 


United  States  Department  of  Agriculture, 

BUREAU    OK  ENTOMOLOGY. 
L.  O.   HOWAKD.   Entomologist  «nd  Chief  of  Bi 


THE  1>Y1\<;  HICKORY  TREES— CA1  8E  VM>  REM  EDI 


Bj    \    D    Hopkins, 
In  Charge  0/  Forttt  limert  Inn  iligatint 

Within  the  past  ten  years  a  large  percentage  of  the 
has  died  in  various  sections  throughout  the  northern 
from    Wisconsin    to    Ver-  . 
mont     and     soul  hv<  ard 
through    tlif    Atlantic 
States  to  centra  I  '  reorgia 
and   to  b   greater  or   less 
extent    within    the   entire 
range  of  natural   growth 
of  t  be  \  a  riou  -  species. 

1  \i  - 

While  there  are  several 
and  sometimes  complicated 
causes  of  the  death  of  the 
trees,  investigations  have 
revealed  the  fact  that  the 
hickory  barkbeetle '  is  by 
far  the  mosl  destructive 
insect  enemy,  and  is,  there- 
fore, in  the  majority  of 
cases,  the  primary  cause  of 
the  dying  of  the  tree-. 


HOW      To      RECOGNIZE      THE 

WORK    or    mi',     it  i<  K<  'i:v 
1!  IRKBEETLE. 


hickor 

t  iir   of 


y  1  rees 
States 


Work  "i"   the  hickory   i>.irkt n     (SeoJ 

a 

■1.   Prlmnri  rr»l 

mines.     1  Author's  Illustration  1 


The  first  evidence  of  the 
presence  anil  work  of  this 
beetle  is  the  premature  dying  or  falling  of  a  few  of  the  leaves  in 
.Tidy  and  August,  caused   by  the   feeding  of  the  adult   or  parent 


,1,1s  quaii  -        Order  Coleoptera,  famil] 


2  THE    DYING    BICKOBY   TREES — CAUSE   AND   REMEDY. 

beetle:-  at  the  base  of  the  leaf  stein  (fig.  4).  but  this  work  alone  does 
not  kill  the  tree-. 

The  next  evidence  of  its  destructive  work  is  the  dying  of  part  of 
a  tree  or  of  all  of  one  or  more  trees.  Tf  the  trees  are  dying  from  the 
attack  of  the  beetle,  an  examination  of  the  inner  bark  and  surface  of 


PIG.  '2. — Complete  brood  galleries  of  the  hickory  bnrkbeetle  on  surface  of  wood. 
(Author's  Illustration.) 


the  wood  on  the  main  trunks  will  reveal  curious  centipede-like  bur- 
rows (figs.  1,  2)  in  the  bark  and  grooved  on  the  surface  of  the  wood. 
These  are  the  galleries  and  burrows  of  the  parent  beetles  and  of  their 
broods  of  young  grubs  or  larvae.  The  girdling  effect  of  these  gal- 
leries is  the  real  cause  of  the  death  of  the  tree-. 


nil.    DYING    III.  K0R1     li;i  i  -      CAU81      1ND    REM]  D1  . 


1 1  \ in  PS  01     nn.   i;i  i  ii  r. 

The  broods  of  the  beetle  pass  the  winter  in  the  bark  of  the  trees 
that  die  during  the  preceding  Bummer  and  fall.  During  the  warm 
days  of  March  and  April  these  overwintered  broods  complete  their 
development  to  the  adult  winged  form  and  during  Maj  and  June 
emerge  through  small  round  holes  in  the  bark  (fig.  3)  and  ll\  to  the 

li\  ing  trees.    They  then  attack  the  i\\  igs  .  fig.  I  |  to  f I  on  the  ba* 

the  leaves  and  tender  bark  and  also  on  the  bark  of  the 

trunks  and  large  branches  of  some  of  the 
living  health)  trees  and  bore  through  the 
bark  to  excavate  their  short,  vertical  i 
galleries  i  fig.   1.  a).    Thi  ire  de- 

posited along  the  sides  of  these  galleries 
and  the  larva'  hatching  from  them  exca- 
vate the  radiating  food  burrows  (fig.  1. 
i>;  fig.  2),  which  serve  to  girdle  the  tree 
or  branch. 

THI   i ; i . m  i  Di  . 

The    following    rec mendations    for 

the  successful  control  of  this  beetle  are 
based  <>n  investigations,  experiments,  and 
demonstrations  conducted  during  the 
past   ten  year-. 

BECOM  MENDATIONS. 

i  1 )  The  best  time  to  conduct  the  con- 
trol work  is  between  October  1  and  May 
I, but  it  must  be  completed  before  the  1st 
to  middle  of  May  in  order  to  destroy  the 
broods  of  the  beetle  before  they  begin  to 
emerge. 

(•2)  Locate  and  mark  the  hickory  trees 
within  an  area  of  several  square  miles 
that  died  during  the  summer  and  fall  and 
those  of  which  pari  or  all  of  the  tops  or 
large  branches  died. 

(■•>>  Fell  the  marked  .lead  trees  ami  cut  out  all  At-.iA  or  infested 
portions  of  the  remaining  marked  tree,  which  Mill  have  sufficient 
life  to  make  a  new  growth. 

Dispose  of  all  infested  trunk,  and  branches  in  such  a  manner 
as  to  kill  the  overwintering  broods  of  the  beetles  in  the  lurk  (a)  by 
utilizing  the  wood  for  commercial  products  and  burning  the  refuse; 
or  (6)    by  utilizing  the  wood  of  the  trunk,  and  I. ranch,-   for 


;ti     I. .-irk     of 

i.i.-kor.v  tr.'-  from  which  broods 
•  <(  th.'  bickorj   barkbeeUe  bare 

tbor'a     III 
Hon.  i 


4  THE   DYING    HICKORY    TREES CAUSE   AND   REMEDY. 

or  (c)  by  placing  the  logs  in  water  and  burning  the  branches  and 
tops;  or  (d)  by  removing  the  infested  bark  from  the  trunks  or  logs 
and  burning  it  with  the  branches  or  as  fuel. 

(5)  So  far  as  combating  the  beetle  is  concerned  it  is  unnecessary 
and  a  waste  of  time  to  dispose  of  trees  or  branches  which  have  been 
dead  12  months  or  more,  because  the  broods  of  the  destructive  beetle 
are  not  to  be  found  in  such  trees. 


Fig.  4. — Injury  by  the  hickory  barkbeetlo  to  the  twigs,  buds,  and  base  of  leaves. 

i  Original,  i 

((>)  Spraying  the  tops  or  brandies  or  the  application  of  any  sub- 
stance as  a  preventive  is  not  to  be  recommended.  Nothing  will  save  a 
1  ice  after  the  main  trunk  is  attacked  by  large  numbers  of  this  beetle 
or  after  the  bark  and  foliage  begin  to  die. 

(7)  The  injuries  to  the  twigs  (fig.  4)  by  this  beetle  do  not  require 
treatment. 

(8)  The  bark  and  wood  of  dying  and  (had  trees  are  almost  inva- 
riably infested   with   manv  kinds  of  bark  and  wood  boring  insects 


Mil     DYING    illi   i\" u\     l'l 


t'Al'SI      \M'    KIM  l.li\  . 


whh  li  can  do  no  harm  to  tinny  tn  I  here  fore  ;i  II  efforts  should  be 

concentrated  on  the  disposal  of  the  broods  of  the  hickory  barkbeetle 
> i-i I i 1 1 i_r  to  the  above  recommendations. 

To  insure  the  protection  of  the  remaining  Living  trees  ii  i-  very 
important  thai  at  leas!  a  large  majority  of  the  dead  infested  and 
partial]^  dead  infested  trees  found  within  an  entire  ana  of  several 
Bquare  miles  be  disposed  of  \\  ithin  a  single  season  in  order  to  kill  the 
broods  of  thi-  beetle.  Therefore  there  should  be  concerted  action  by 
all  <>\\ ners  of  hickory  tree-. 

On  account  of  the  value  of  the  hickory  for  shade  and  outs  and  for 
many  commercial  wood  products  it  is  important  that  the  people  of  a 
community,  county,  or  State  who  are  in  any  manner  interested  in  1 1 1  -  - 
protection  of  hickory  tnc-  should  give  encouragement  and  support  to 
any  concerted  or  cooperative  effort  on  the  pari  of  the  owner-  toward 
the  propei'  control  of  the  hickory  barkbeetle. 

Approved : 

.1  \  Ml>   Wii  SON, 

try  of  .  I [ir'"  ult\ 

W  k8HINGT0N,   I  '.  (  '..  Nov*  '.   1911. 


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